1. Technical Field
The present invention relates to a printing apparatus, and more specifically relates to a method for processing at the time of a reset and to a head cleaning processing method for an ink jet printing apparatus.
2. Background Art
An ink jet printing apparatus which ejects ink from an ink jet head for printing typically requires regular maintenance or cleaning processing to maintain reliability of the ink jet head; regular maintenance prevents problems such as clogged nozzles due to increased viscosity within the nozzles due to drying of ink, which results in defective printing.
Such cleaning processing is generally managed based on a timer, etc., according to the time elapsed from the last cleaning operation and the capped state of the ink jet head.
Also, if a printing apparatus which is controlled by a host computer is installed in a remote location from the host computer, as is the case for a POS printer or a network-printer, it is necessary to perfectly control the printer by remote-control. Accordingly, it has been required to execute similar initialization processing as the initialization processing at the time the printer is powered on in response to a reset signal from the host computer, and in cleaning operations, an initialization level of cleaning has been executed, consuming large quantities of ink.
The reset signal can be issued at various times, including when the host computer is turned on, when the OS (operating system) boots up, when an application boots up, and when an application starts printing. As a result, multiple reset signals can be sent to the printer at relatively short time intervals depending upon the host computer type, application, and printer driver, etc., (hereinafter, such a reset signal is referred to as an "unintentional reset signal").
In such a case, a conventional printer executes initialization level cleaning each time, this consumes more ink than is really necessary. This results in higher operating costs, decreasing the quantity of ink actually used, and is not desirable in terms of resource conservation and environmental protection, producing increased numbers of expended ink cartridges due to more frequent changes of ink cartridges.
Also, in order to maintain printer reliability, it has been impossible to totally ignore reset signals supplied from the outside since reset signals may be generated for a variety of reasons.
Accordingly, an object of the present invention is to provide a printing apparatus and cleaning processing method which allow reduction in the quantity of ink consumed by avoiding excessive cleaning while maintaining reliability of the printing apparatus.